1. Field of the Invention
The present invention relates generally to a method for preparing organoxy-functional silanes and more particularly to a novel method for such production which utilizes the reaction of halosilanes and hydroxy compounds in the presence of a polymer that includes carbon-bonded fluorine.
2. Description of the Prior Art
Organoxy-functional silanes, for example alkoxysilanes and phenoxysilanes, are in wide use as water repellents and surface-treatment agents. This class of compounds has heretofore been prepared mainly by the reaction (dehydrohalogenation) between a halosilane and a hydroxy compound. The halosilane precursor has been synthesized, for example, by the direct reaction of halohydrocarbon with silicon metal, the reaction of silicon metal with hydrogen halide, and catalyzed hydrosilylation between alkenes and SiH-functional halosilanes.
One drawback to this method for the preparation of organoxy-functional silane is associated with the vigorous foaming that can occur during the dehydrohalogenation reaction due to the evolved hydrogen halide gas and volatilized hydroxy compound. This has made it necessary to reduce the per-unit timefeed of hydroxy compound to the reactor, which hinders productivity.